/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright 1997-2007 Sun Microsystems, Inc.  Portions Copyrighted 2008 Richard Schilling.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License. You can obtain
 * a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
 * or glassfish/bootstrap/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
 * Sun designates this particular file as subject to the "Classpath" exception
 * as provided by Sun in the GPL Version 2 section of the License file that
 * accompanied this code.  If applicable, add the following below the License
 * Header, with the fields enclosed by brackets [] replaced by your own
 * identifying information: "Portions Copyrighted [year]
 * [name of copyright owner]"
 *
 * Contributor(s): Richard Schilling (coderroadie@gmail.com)
 *
 * If you wish your version of this file to be governed by only the CDDL or
 * only the GPL Version 2, indicate your decision by adding "[Contributor]
 * elects to include this software in this distribution under the [CDDL or GPL
 * Version 2] license."  If you don't indicate a single choice of license, a
 * recipient has the option to distribute your version of this file under
 * either the CDDL, the GPL Version 2 or to extend the choice of license to
 * its licensees as provided above.  However, if you add GPL Version 2 code
 * and therefore, elected the GPL Version 2 license, then the option applies
 * only if the new code is made subject to such option by the copyright
 * holder.
 */

package javax.mail;

import java.io.*;
import java.net.*;
import java.util.*;
import javax.mail.event.*;

/**
 * An abstract class that models a message store and its
 * access protocol, for storing and retrieving messages.
 * Subclasses provide actual implementations.
 * <p>
 * Note that <code>Store</code> extends the <code>Service</code> class, which
 * provides many common methods for naming stores, connecting to stores, and
 * listening to connection events.
 * 
 * @author John Mani
 * @author Bill Shannon
 * @see javax.mail.Service
 * @see javax.mail.event.ConnectionEvent
 * @see javax.mail.event.StoreEvent
 */

public abstract class Store extends Service {

    /**
     * Constructor.
     * 
     * @param session Session object for this Store.
     * @param urlname URLName object to be used for this Store
     */
    protected Store(Session session, URLName urlname) {
        super(session, urlname);
    }

    /**
     * Returns a Folder object that represents the 'root' of
     * the default namespace presented to the user by the Store.
     * 
     * @return the root Folder
     * @exception IllegalStateException if this Store is not connected.
     */
    public abstract Folder getDefaultFolder() throws MessagingException;

    /**
     * Return the Folder object corresponding to the given name. Note
     * that a Folder object is returned even if the named folder does
     * not physically exist on the Store. The <code>exists()</code> method on
     * the folder object indicates whether this folder really
     * exists.
     * <p>
     * Folder objects are not cached by the Store, so invoking this method on
     * the same name multiple times will return that many distinct Folder
     * objects.
     * 
     * @param name The name of the Folder. In some Stores, name can
     *            be an absolute path if it starts with the
     *            hierarchy delimiter. Else it is interpreted
     *            relative to the 'root' of this namespace.
     * @return Folder object
     * @exception IllegalStateException if this Store is not connected.
     * @see Folder#exists
     * @see Folder#create
     */
    public abstract Folder getFolder(String name) throws MessagingException;

    /**
     * Return a closed Folder object, corresponding to the given
     * URLName. The store specified in the given URLName should
     * refer to this Store object.
     * <p>
     * Implementations of this method may obtain the name of the actual folder
     * using the <code>getFile()</code> method on URLName, and use that name to
     * create the folder.
     * 
     * @param url URLName that denotes a folder
     * @see URLName
     * @exception IllegalStateException if this Store is not connected.
     * @return Folder object
     */
    public abstract Folder getFolder(URLName url) throws MessagingException;

    /**
     * Return a set of folders representing the <i>personal</i> namespaces
     * for the current user. A personal namespace is a set of names that
     * is considered within the personal scope of the authenticated user.
     * Typically, only the authenticated user has access to mail folders
     * in their personal namespace. If an INBOX exists for a user, it
     * must appear within the user's personal namespace. In the
     * typical case, there should be only one personal namespace for each
     * user in each Store.
     * <p>
     * This implementation returns an array with a single entry containing the
     * return value of the <code>getDefaultFolder</code> method. Subclasses
     * should override this method to return appropriate information.
     * 
     * @exception IllegalStateException if this Store is not connected.
     * @return array of Folder objects
     * @since JavaMail 1.2
     */
    public Folder[] getPersonalNamespaces() throws MessagingException {
        return new Folder[] { getDefaultFolder() };
    }

    /**
     * Return a set of folders representing the namespaces for <code>user</code>
     * . The namespaces returned represent the
     * personal namespaces for the user. To access mail folders in the
     * other user's namespace, the currently authenticated user must be
     * explicitly granted access rights. For example, it is common for
     * a manager to grant to their secretary access rights to their
     * mail folders.
     * <p>
     * This implementation returns an empty array. Subclasses should override
     * this method to return appropriate information.
     * 
     * @exception IllegalStateException if this Store is not connected.
     * @return array of Folder objects
     * @since JavaMail 1.2
     */
    public Folder[] getUserNamespaces(String user) throws MessagingException {
        return new Folder[0];
    }

    /**
     * Return a set of folders representing the <i>shared</i> namespaces.
     * A shared namespace is a namespace that consists of mail folders
     * that are intended to be shared amongst users and do not exist
     * within a user's personal namespace.
     * <p>
     * This implementation returns an empty array. Subclasses should override
     * this method to return appropriate information.
     * 
     * @exception IllegalStateException if this Store is not connected.
     * @return array of Folder objects
     * @since JavaMail 1.2
     */
    public Folder[] getSharedNamespaces() throws MessagingException {
        return new Folder[0];
    }

    // Vector of Store listeners
    private volatile Vector storeListeners = null;

    /**
     * Add a listener for StoreEvents on this Store.
     * <p>
     * The default implementation provided here adds this listener to an
     * internal list of StoreListeners.
     * 
     * @param l the Listener for Store events
     * @see javax.mail.event.StoreEvent
     */
    public synchronized void addStoreListener(StoreListener l) {
        if (storeListeners == null)
            storeListeners = new Vector();
        storeListeners.addElement(l);
    }

    /**
     * Remove a listener for Store events.
     * <p>
     * The default implementation provided here removes this listener from the
     * internal list of StoreListeners.
     * 
     * @param l the listener
     * @see #addStoreListener
     */
    public synchronized void removeStoreListener(StoreListener l) {
        if (storeListeners != null)
            storeListeners.removeElement(l);
    }

    /**
     * Notify all StoreListeners. Store implementations are
     * expected to use this method to broadcast StoreEvents.
     * <p>
     * The provided default implementation queues the event into an internal
     * event queue. An event dispatcher thread dequeues events from the queue
     * and dispatches them to the registered StoreListeners. Note that the event
     * dispatching occurs in a separate thread, thus avoiding potential deadlock
     * problems.
     */
    protected void notifyStoreListeners(int type, String message) {
        if (storeListeners == null)
            return;

        StoreEvent e = new StoreEvent(this, type, message);
        queueEvent(e, storeListeners);
    }

    // Vector of folder listeners
    private volatile Vector folderListeners = null;

    /**
     * Add a listener for Folder events on any Folder object
     * obtained from this Store. FolderEvents are delivered to
     * FolderListeners on the affected Folder as well as to
     * FolderListeners on the containing Store.
     * <p>
     * The default implementation provided here adds this listener to an
     * internal list of FolderListeners.
     * 
     * @param l the Listener for Folder events
     * @see javax.mail.event.FolderEvent
     */
    public synchronized void addFolderListener(FolderListener l) {
        if (folderListeners == null)
            folderListeners = new Vector();
        folderListeners.addElement(l);
    }

    /**
     * Remove a listener for Folder events.
     * <p>
     * The default implementation provided here removes this listener from the
     * internal list of FolderListeners.
     * 
     * @param l the listener
     * @see #addFolderListener
     */
    public synchronized void removeFolderListener(FolderListener l) {
        if (folderListeners != null)
            folderListeners.removeElement(l);
    }

    /**
     * Notify all FolderListeners. Store implementations are
     * expected to use this method to broadcast Folder events.
     * <p>
     * The provided default implementation queues the event into an internal
     * event queue. An event dispatcher thread dequeues events from the queue
     * and dispatches them to the registered FolderListeners. Note that the
     * event dispatching occurs in a separate thread, thus avoiding potential
     * deadlock problems.
     * 
     * @param type type of FolderEvent
     * @param folder affected Folder
     * @see #notifyFolderRenamedListeners
     */
    protected void notifyFolderListeners(int type, Folder folder) {
        if (folderListeners == null)
            return;

        FolderEvent e = new FolderEvent(this, folder, type);
        queueEvent(e, folderListeners);
    }

    /**
     * Notify all FolderListeners about the renaming of a folder.
     * Store implementations are expected to use this method to broadcast
     * Folder events indicating the renaming of folders.
     * <p>
     * The provided default implementation queues the event into an internal
     * event queue. An event dispatcher thread dequeues events from the queue
     * and dispatches them to the registered FolderListeners. Note that the
     * event dispatching occurs in a separate thread, thus avoiding potential
     * deadlock problems.
     * 
     * @param oldF the folder being renamed
     * @param newF the folder representing the new name.
     * @since JavaMail 1.1
     */
    protected void notifyFolderRenamedListeners(Folder oldF, Folder newF) {
        if (folderListeners == null)
            return;

        FolderEvent e = new FolderEvent(this, oldF, newF, FolderEvent.RENAMED);
        queueEvent(e, folderListeners);
    }
}
